Conventional cathode ray tube (CRT) displays are unsuitable for use in multimedia applications because of their large volume. Therefore, many flat panel display techniques such as liquid crystal display (LCD), plasma display panel (PDP), and field emission display (FED) have been recently developed. These display techniques can manufacture a thin, light, short and small monitor, and thus these techniques are and will be the mainstream technology. In these techniques, the plasma display panel (PDP) is attracting attention in the field of displays as a full-color display apparatus having a large size display area and is especially popularly utilized in large-size televisions or outdoor display panels. This is because it is a high quality display as a result of it being a self-light emitting type with a wide angle of visibility and high speed of response as well as being suited to upsizing due to a simple manufacturing process.
A color PDP is a display in which ultraviolet rays are produced by gas discharge to excite phosphorus so that visible light is emitted therefrom to perform a display operation. Depending upon a discharge mode, the color PDP is classified as an alternating current (AC) or a direct current (DC) type. In the AC-type PDP, an electrode is covered with a protective layer. The AC-type PDP has inherent characteristics of long life and high brightness. Therefore, the AC-type PDP is generally superior to the DC-type PDP in luminance, luminous efficiency and lifetime.
PDP utilizes an external voltage to cause gas discharge inside the panel to produce the ultraviolet rays. The ultraviolet rays excite R, G, and B phosphorus to generate the visible R, G, and B lights. Therefore, the reddish orange color light caused by the gas discharge and the chromaticity purity of R, G, and B phosphorus apparently influences the output color of the PDP module. A good white balance of the PDP module is very important to produce a good color display so the balance of fudamental colors emitted by the R, G, and B phosphorus is important. However, even if a surface filter of the PDP module can filter the reddish orange color and modify the chromaticity of the PDP output, the color space of the PDP module still is different from the color space of the video specification, such as National Television System Committee (NTSC), European Broadcasting Union (EBU) or Standard RGB (sRGB). If there is not sufficient color space transformation, the output color of the PDP module may display visible color deviation. For example, the sky may be too green and a white cloud may be too yellow in a conventional PDP module. In particular, if the image quality is very bad, skin color may become too red or too green when the video specification of the PDP module and the video image signals are different.
FIG. 1 illustrates various video specifications in a CIE 1931 chromaticity diagram. The CIE 1931 chromaticity diagram is an international chromaticity system provided by the Commission Internationale de I'Eclairage (CIE) in 1931 and is well known to persons skilled in the art. Referring to FIG. 1, region 110 illustrates a color space of PDP module image output. Region 120 illustrates a color space of PDP module image output with a surface filter. Region 130 illustrates a color space of NTSC image output specification. Region 140 illustrates a color space of EBU image output specification. Because all regions 110, 120, 130, and 140 do not fully overlap, the PDP video image output cannot fully satisfy these video specification requirements. Therefore, the PDP image output has to be modified to satisfy the respective video specification requirement according to the color space thereof. Otherwise, the image output may cause some color deviation.
A conventional PDP utilizes a Capsulated Color Filter (CCF) to adjust the color space of the video image output, but the CCF still demonstrates some color deviation to the video specification due to limitation of the filter material. Furthermore, the CCF still is expensive and complicated to manufacture and therefore the manufacturing process is very difficult and the yield rate is low. Additionally, even a PDP with CCF still cannot fulfill every different video specification requirement.